In Harris v. CSX Transportation, Inc., No. 12-1135 (W. Va. Nov. 13, 2013), the Supreme Court of Appeals of West Virginia reviewed the trial court’s decision to exclude the testimony of plaintiff’s experts that plaintiff’s exposure to diesel exhaust fumes during his work as a railroad employee caused him to develop cancer. In excluding the experts’ testimony, the trial court had conducted its own review of the epidemiologic literature and concluded that it did not support plaintiff’s experts’ opinion. The Supreme Court reversed, ruling that in doing so, the trial court had overstepped the proper bounds of its gatekeeper function with respect to scientific experts. The Supreme Court held that the trial court should have limited itself to determining whether the methodologies that the experts used (such as reviewing the epidemiologic literature) to connect the fumes to cancer were reliable, and should have left the ultimate decision whether the plaintiff’s experts reached correct conclusions based on those methodologies to the jury.